The field of art to which this invention pertains is the purification of a diolefin hydrocarbon stream containing trace quantities of acetylene compounds. The production of diolefins is well known and widely practiced to produce a wide variety of products and precursor products utilizing a variety of diolefin production processes including naphtha cracking processes and by-products from fluid catalytic cracking processes. Most of these diolefin production processes produce undesirable trace quantities of acetylene. One technique which is used purify diolefin streams selectively hydrogenates the acetylene while minimizing the destruction or hydrogenation of the diolefin compounds.
The selective hydrogenation of the acetylene compounds is generally conducted in the presence of a selective hydrogenation catalyst and hydrogen and conducted at an elevated pressure and temperature. Such selective hydrogenation catalysts are well known in the art and include, for example, a catalyst containing copper metal associated with one or more activator metals impregnated on an alumina support. During the acetylene hydrogenation polymers are formed and deposited on the catalyst thereby reducing the activity of the catalyst. One known method of regenerating spent or partially spent catalyst is to perform a controlled carbon bum and subsequent metal reduction to remove catalyst contaminants which are formed as an undesirable by-product of the acetylene hydrogenation. The carbon bum regeneration techniques necessarily require that the reaction zone containing the spent catalyst be taken off-line and that ancillary regeneration equipment be provided.